KR20210015443A - Polarizing plate and display appartus comprising the same - Google Patents

Abstract

Provided are a polarizing plate and a display device including the same. The polarizing plate provides a polarizer and a protection film laminated on at least one surface of the polarizer. The polarizing plate has at least a depolarization region in an in-plane direction, and the depolarization region has a maximum absorbance of 0.5-1.5 among wavelengths of 380-420 nm. In the depolarization region, the ratio of the light transmittance at a wavelength of 590 nm to the light transmittance at a wavelength of 400 nm is 1-2. The polarizing plate has the depolarization region allowing for significantly improved camera performance.

Description

A polarizing plate and a display device including the same TECHNICAL FIELD [POLARIZING PLATE AND DISPLAY APPARTUS COMPRISING THE SAME}

The present invention relates to a polarizing plate and a display device including the same. More specifically, the present invention relates to a polarizing plate having a polarization canceling area capable of improving color and clarity of an image and preventing image deformation when capturing an image through a polarization canceling area, and a display device including the same.

The polarizing plate has a function of polarizing and emitting light emitted from a liquid crystal panel among optical display devices. The polarizing plate includes a polarizer and a protective film laminated on at least one surface of the polarizer. In general, an optical display device has various functions such as a camera and a video call, as well as a display function for showing a screen. Since the polarizing plate cannot transmit more than 50% of the amount of light due to the polarization function, visibility may be deteriorated when the polarizing plate is used as it is in the camera area. To implement this, it is necessary to form a polarization canceling region in at least a portion of the polarizing plate.

Recently, as the tendency to shoot clearer screens with high resolution has increased, there has been a limit to only the existing polarization canceling area. Previously, the function as a camera was implemented by increasing the light transmittance of the polarization canceling area. However, just by increasing the light transmittance, the color and sharpness of the captured image is not good, and the image may be severely deformed.

Background technology of the present invention is disclosed in Korean Patent Application Publication No. 2017-0037854.

It is an object of the present invention to provide a polarizing plate provided with a polarization canceling area that is excellent in color and brightness, and enables a clear image to be captured so that there is no image distortion, thereby remarkably improving camera performance.

Another object of the present invention is to provide a polarizing plate that can be applied to an infrared sensor or the like because the transmission performance of the polarization canceling region is remarkably excellent.

One aspect of the present invention is a polarizing plate.

1.The polarizing plate includes a polarizer and a protective film laminated on at least one surface of the polarizer, the polarizing plate has at least a polarization canceling region in an in-plane direction, and the polarization canceling region has a maximum absorbance of 0.5 in a wavelength range of 380 nm to 420 nm. To 1.5, and in the polarization canceling region, the ratio of the light transmittance at the wavelength of 590 nm to the light transmittance at the wavelength of 400 nm is 1 to 2.

2.1, the polarizing region is eliminated I ₃ ^- can be a ratio of 1 to 2 at a concentration of ions ^- I ₅ of the concentration of the ion.

In 3.1-2, the polarization canceling region may have a minimum absorbance of 0.1 to 1 in a wavelength range of 380 nm to 420 nm.

In 4.1-3, the polarizing plate further includes a polarization region, and in the polarization region, a maximum absorbance in a wavelength region of 380 nm to 420 nm may be greater or less than a maximum absorbance in a wavelength region of 380 nm to 420 nm in the polarization cancellation region.

In 5.4, in the polarization region, a ratio of a light transmittance at a wavelength of 590 nm to a light transmittance at a wavelength of 400 nm may be less than a ratio of the light transmittance at the polarization canceling region.

6.4, the polarizing region is I ₃ ^- may be greater than the concentration of the ^non-ion-I ₅ of the concentration of the ^ion I ₃ ratio of the polarization relieve areas of concentration of the ^ion-I ₅ of the concentration of the ion.

In 7.1-6, the polarizer may include a polarizer dyed with at least one of iodine and a dichroic dye.

The display device of the present invention includes the polarizing plate of the present invention.

The present invention provides a polarizing plate provided with a polarization canceling area that is excellent in color and brightness, and enables a clear image to be captured so that there is no image distortion, thereby remarkably improving camera performance.

1 shows absorbance according to wavelength in a polarization canceling region among polarizing plates of Examples and Comparative Examples. The X axis is wavelength and the Y axis is absorbance.
2 is a maximum absorbance in a wavelength range of 380 nm to 420 nm in a polarization cancellation region according to energy per pulse per laser irradiation unit area at each laser irradiation wavelength in an embodiment.
FIG. 3 shows the ratio of the light transmittance at the wavelength of 590 nm to the light transmittance at the wavelength of 400 nm in the polarization canceling region according to the energy per pulse of laser irradiation at each laser irradiation wavelength in an embodiment.
4 is a visual observation result of a polarization canceling region of Example 1, Comparative Example 2, and Comparative Example 3. FIG.

The present invention will be described in detail so that those of ordinary skill in the art can easily implement the present invention by the accompanying embodiments. The present invention may be implemented in various different forms, and is not limited to the embodiments described herein.

When describing the numerical range in the present specification, "X to Y" means X or more and Y or less (X≤ and ≤Y).

Hereinafter, a polarizing plate according to an embodiment of the present invention will be described.

The polarizing plate includes a polarizer and a protective film laminated on at least one surface of the polarizer. The polarizing plate includes a polarization canceling region in at least a portion of the plane of the polarizing plate.

The polarization canceling region is a region in which polarization performance inherent in the polarizing plate is not present or lowered when the polarizing plate is applied to an image display device such as a mobile phone, a monitor, or an infrared sensor, and may be used as a region in which a camera is installed. The polarization canceling region may be formed to be 90% or less, or 50% or less of the plane of the polarizing plate, but is not limited thereto.

The polarization canceling region may have a single light transmittance at a wavelength of 380 nm to 780 nm of 50% or more, specifically 50% to 100%, and 55% to 100%. In addition, the polarization canceling region may have a polarization degree of 50% or less, specifically 0% or more and 5% or less. In the above range, the polarization canceling region can be applied to a camera for image capturing.

In the polarization canceling region, the ratio of the light transmittance at the wavelength 590 nm (the light transmittance at the wavelength 590 nm/the light transmittance at the wavelength 400 nm) to the light transmittance at a wavelength of 400 nm (hereinafter referred to as “the ratio of the light transmittance”) is 1 to 2, and in addition, the maximum absorbance in the wavelength range of 380 nm to 420 nm is 0.5 to 1.5.

In general, the polarization canceling region has a light transmittance of 40% or more at a wavelength of 380 nm to 780 nm, so that a screen can be photographed when applied with a camera. In addition, in the polarization canceling region, the light transmittance tends to increase as the wavelength increases. However, there is a limit in optimizing the color and brightness of an image when capturing an image through a camera by simply increasing the light transmittance of the polarization canceling region.

The present invention controls the light transmittance at a wavelength of 590 nm to 1 to 2 with respect to the light transmittance at a wavelength of 400 nm in the polarization canceling region, while additionally securing the maximum absorbance of 0.5 to 1.5 in the wavelength range of 380 nm to 420 nm. While improving the color and brightness of an image, it is possible to prevent deformation of the image.

The polarization canceling region of the present invention will be described in more detail.

In the polarization cancellation region, the maximum absorbance at a wavelength of 380 nm to 420 nm was considered. The inventors of the present invention have confirmed that the sharpness, color and brightness of an image through the polarization canceling region can be determined not only according to the light transmittance of the polarization canceling region, but also the absorbance at a short wavelength, particularly a wavelength of 380 nm to 420 nm. Accordingly, the maximum absorbance at a wavelength of 380 nm to 420 nm was controlled to a specific range of 0.5 to 1.5 of the present invention. The wavelength of 380 nm to 420 nm is a short wavelength region, and absorbance in this region may affect the sharpness of the image. Preferably, the maximum absorbance may be 0.9 to 1.5.

In the depolarization region, the ratio of light transmittance was also considered. In general, the light transmittance of the polarization cancellation region increases as the wavelength increases. However, the inventors of the present invention have further improved the light transmittance according to the wavelength, and further the ratio of the light transmittance becomes 1 to 2, which is a specific range of the present invention, so that the sharpness, color and brightness of the image through the polarization canceling region are excellent. It was confirmed that there was no deformation.

When the ratio of the maximum absorbance and the light transmittance is satisfied, the sharpness and color of the image through the polarization canceling area are excellent, and there is no deformation of the image. The specific means for reaching the ratio of the maximum absorbance and light transmittance will be described in more detail below.

The polarization canceling region may have a light transmittance of 30% or more at a wavelength of 400 nm, specifically 30% to 80%. Within the above range, the light transmittance ratio of the present invention can be easily reached, and information on the blue region is acquired by improving the short wavelength transmittance, thereby facilitating camera image processing.

The polarization canceling region may have a light transmittance of 50% or more, specifically 50% to 95%, at a wavelength of 590 nm. In the above range, it is possible to easily reach the light transmittance ratio of the present invention, and to form a more neutral, colorless, high-transmission portion.

In one embodiment, the polarizing region is eliminated I ₃ ^- is can be a 1 to 2 for the concentration of the ion I ₅ ^- the concentration of the ion ratio ^{_{(I 5 - - / I 3}} ). Generally, the iodide ion contained in the polarizer by the decomposition (I ₅ ^{- -,} I _3, etc.) to form the polarization domain eliminated. In the present invention, I ₅ ^- may form a 1 to 2 so that the short wavelength and a more neutral than the lower the ratio of long wavelength range, and no parts of high transmission saekgalyi ^- / I _3. By man haeri I ₅ ^{- -} I ₅ of the long-wavelength region due to the rapid degradation / I ₃ ^- ratio grows to greater than 2 may result in a reduction substance transmittance and Yellowish color.

In one embodiment, the polarization canceling region may have a minimum absorbance of 0.1 to 1, specifically 0.1 to 0.5 in a wavelength range of 380 nm to 420 nm.

The polarization canceling region may be manufactured by subjecting a polarizer or a laminate in which a protective film is laminated on at least one surface of the polarizer to be subjected to a laser treatment described below.

The polarizer may include a polarizer dyed with at least one of iodine and a dichroic dye. A method of manufacturing a polarizer may be manufactured according to a conventional method known to those skilled in the art.

The polarizer can be manufactured by dyeing, stretching, crosslinking, and complementary color processes. In the manufacturing method of the polarizer, the order of dyeing and stretching is not limited. That is, the polyvinyl alcohol-based film may be dyed and then stretched, or stretched and then dyed, or dyeing and stretching may be performed simultaneously.

As the polyvinyl alcohol-based film, a conventional polyvinyl alcohol-based film used in manufacturing a conventional polarizer may be used. Specifically, a film formed of polyvinyl alcohol or a derivative thereof may be used. The degree of polymerization of polyvinyl alcohol may be 1000 　 to 5000, the saponification degree may be 80 mol% to 100 mol%, the thickness may be 1 µm to 30 µm, specifically 3 µm to 30 µm, in the above range , It can be used to manufacture a thin polarizer.

Before the polyvinyl alcohol-based film is dyed or stretched, it may be washed with water and swollen. By washing the polyvinyl alcohol-based film with water, foreign matter on the surface of the polyvinyl alcohol-based film can be removed. By swelling the polyvinyl alcohol-based film, it is possible to improve dyeing or stretching of the polyvinyl alcohol-based film. The swelling treatment can be performed by leaving the polyvinyl alcohol-based film in an aqueous solution of the swelling tank as known to those skilled in the art. The temperature of the swelling bath and the swelling treatment time are not particularly limited. The swelling tank may further contain boric acid, inorganic acid, surfactant 　, and the like, and their content may be adjusted.

The polyvinyl alcohol-based film can be dyed by dyeing the polyvinyl alcohol-based film in a dyeing tank containing at least one of iodine and dichroic dye. In the dyeing process, the polyvinyl alcohol-based film is immersed in the dyeing solution, and the dyeing solution may be an aqueous solution containing iodine and a dichroic dye. Specifically, iodine is provided from an iodine-based dye, and the iodine-based dye may include one or more of potassium iodide, hydrogen iodide, lithium iodide, sodium iodide, zinc iodide, lithium iodide, aluminum iodide, lead iodide, and copper iodide. . The dyeing solution may be an aqueous solution containing 1% by weight to 5% by weight of at least one of iodine and dichroic dyes. In the above range, it can be used in a display device with a polarization degree in a predetermined range.

The temperature of the dyeing bath may be 20°C to 45°C, and the immersion time of the dyeing bath of the polyvinyl alcohol-based film may be 10 seconds to 300 seconds. In the above range, a polarizer having a high degree of polarization may be implemented.

By stretching the dyed polyvinyl alcohol-based film in a drawing tank, the polyvinyl alcohol-based film may have polarization by oriented at least one of iodine and dichroic dye. Specifically, stretching can be performed by both dry stretching and wet stretching. Dry stretching may be interroll stretching, compression stretching, heating roll stretching, and the like, and wet stretching may be performed in a wet stretching tank containing water at 35°C to 65°C. The wet stretching tank may further include boric acid to enhance the stretching effect.

The polyvinyl alcohol-based film can be stretched at a predetermined draw ratio, specifically, the total draw ratio can be stretched to be 5 to 7 times, specifically 5.5 to 6.5 times, and the cutting phenomenon of the polyvinyl alcohol-based film stretched in the above range , It is possible to prevent the occurrence of wrinkles, etc., and can implement a polarizer with high polarization degree and transmittance. Although stretching may be performed in single-stage stretching as uniaxial stretching, it is also possible to prevent breakage while manufacturing a thin polarizer by multi-stage stretching such as 2-stage or 3-stage stretching.

In the above description, the polyvinyl alcohol-based film is dyed and then stretched, but dyeing and stretching may be performed in the same reaction tank.

Before or after the dyed polyvinyl alcohol-based film is stretched, the stretched polyvinyl alcohol-based film may be crosslinked in a crosslinking bath. Crosslinking is a process in which at least one of iodine and dichroic dyes is more strongly dyed to the polyvinyl alcohol-based film, and boric acid may be used as the crosslinking agent. Phosphoric acid compounds, potassium iodide, and the like may be further included in order to increase the crosslinking effect.

The dyed and stretched polyvinyl alcohol-based film may be treated with a complementary color in a complementary color tone. The complementary color treatment is to immerse the dyed and stretched polyvinyl alcohol-based film in a complementary color bath containing a complementary color solution containing potassium iodide. Through this, the color value of the polarizer can be lowered and the iodine anion I ^- in the polarizer can be removed to improve durability. The temperature of the complementary color bath may be 20°C to 45°C, and the immersion time of the complementary color bath of the polyvinyl alcohol-based film may be 10 seconds to 300 seconds.

The polarizer may have a thickness of 10 μm to 50 μm, specifically 10 μm to 30 μm. In the above range, it can be used for a polarizing plate.

Polarization solved region can be formed by less per unit area of the polarizer the energy per pulse 0J / cm ² and greater than the pulse 0.17J / cm ² and the pulse irradiation of a femtosecond laser.

In the present invention, "energy per pulse per unit area" is defined as a value obtained by dividing the total energy irradiated to the polarizer per pulse by the total area irradiated with the femtosecond laser in each of the femtosecond laser irradiation wavelengths.

In the present invention, the polarizer is irradiated with a femtosecond laser, but by controlling the energy per pulse per unit area described above, I ₃ ^- ions and I ₅ ^- ions of the iodine ions in the polarizer are uniformly decomposed from each other, so that the above-described maximum absorbance and light It was allowed to reach the transmittance ratio. In addition, the number of wavelengths irradiated in the laser irradiation wavelength range described below may be adjusted.

When the energy per pulse per unit area is 0.17J/cm ² ㆍWhen the polarizer is irradiated with a femtosecond laser, the degree of decomposition between I ₃ ^- ions and I ₅ ^- ions among the iodine ions contained in the polarizer increases significantly. . That is, iodide ion I ₅ ^- of the ion I ₃ ^- more degradation than the ion being I ₅ ^- ion I ₃ ^- The decomposition ratio of the ions becomes non-uniform, which results wavelength of the present invention 380nm to a maximum absorbance at 420nm, and The polarization canceling region having a light transmittance ratio cannot be implemented. In addition, when the energy per pulse per unit area exceeds 0.17 J/cm ² ㆍpulse, excessive pulse energy irradiated to the polarizer may be transferred to the polyvinyl alcohol-based film constituting the polarizer, thereby causing thermal deformation of the polarizer.

FIG. 2 is a maximum absorbance in a wavelength range of 380 nm to 420 nm in a polarization resolution region according to energy per pulse per unit area at one wavelength during femtosecond laser irradiation in an embodiment. On the other hand, although not shown in FIG. 2, the energy per pulse per unit area is controlled to 0.17 J/cm ² ㆍpulse or less, and at the same time, the number of femtoseconds irradiated in the wavelength 510 nm to 520 nm region and/or the wavelength 340 nm to 346 nm region is changed. In this case, a maximum absorbance of 0.5 to 1.0 can be achieved.

3 shows a ratio of light transmittance at a wavelength of 590 nm to light transmittance at a wavelength of 400 nm in a polarization canceling region according to energy per pulse per unit area at one wavelength during femtosecond laser irradiation in an embodiment.

Referring to FIG. 3, as the energy per pulse per unit area increases, the light transmittance ratio increases. However, it can be seen that, as the energy per pulse per unit area exceeds 0.17 J/cm ² ㆍpulse, the ratio of the maximum absorbance and the light transmittance of the polarization canceling region increases rapidly.

In one embodiment, the energy per pulse per unit area may be 0.01J/cm ² ㆍpulse to 0.17 J/cm ² ㆍpulse.

In one embodiment, in the present invention, a polarization cancellation region may be implemented by irradiating a femtosecond laser only in a wavelength range of 510 nm to 520 nm. When the femtosecond laser is irradiated in the wavelength region, a polarization canceling region having a ratio of maximum absorbance and light transmittance at a wavelength of 380 nm to 420 nm of the present invention may be implemented. At wavelengths exceeding 520nm, the energy per pulse per unit area is 0.17J/cm ² ㆍIn case of irradiation higher than the pulse I ₃ ^- Compared to ions I ₅ ^-As ions are rapidly decomposed, the light transmittance ratio exceeds 2 or the wavelength ranges from 380 nm to 380 nm. The maximum absorbance at 420 nm also exceeds 1.5.

Specifically, in the wavelength range of 510nm to 520nm, a femtosecond laser having a wavelength of 510nm, 511nm, 512nm, 513nm, 514nm, 515nm, 516nm, 517nm, 518nm, 519nm, 520nm, and preferably 515nm may be selected.

In another embodiment, in the present invention, a polarization cancellation region may be implemented by irradiating at least two femtosecond lasers each selected from a wavelength range of 340 nm to 346 nm and a wavelength range of 510 nm to 520 nm. In the wavelength region, a polarization canceling region having a ratio of maximum absorbance and light transmittance at a wavelength of 380 nm to 420 nm of the present invention may be implemented. In addition, even when the polarizer or the polarizing plate is left at a high temperature and high humidity for a long period of time, a change in the degree of polarization and/or light transmittance in the polarization canceling region is low, and thus reliability may be excellent.

Specifically, a femtosecond laser having a wavelength of 340 nm, 341 nm, 342 nm, 343 nm, 344 nm, 345 nm, 346 nm, and preferably 343 nm may be selected in the wavelength range of 340 nm to 346 nm.

In one embodiment, the femtosecond laser may be irradiated by selecting one femtosecond laser in a wavelength region of 510 nm to 520 nm, and one femtosecond laser in a wavelength region of 340 nm to 346 nm.

The effects of the present invention may be better implemented by controlling the intensity of the femtosecond lasers irradiated in each region while the femtosecond lasers respectively selected in the above-described wavelength region are irradiated. Specifically, the femtosecond laser irradiated in a wavelength range of 340 nm to 346 nm has an energy per pulse per unit area of 0.01 J/cm ² ㆍpulse to 0.17 J/cm ² ㆍpulse, preferably 0.11 J/cm ² ㆍpulse to 0.17 J/ cm ² ㆍCan be irradiated with pulses. Fs is irradiated at a wavelength of 510nm to 520nm region laser energy per pulse per unit area of 0.01J / cm ² and a pulse to 0.17J / cm ² and a pulse, preferably 0.15J / cm ² and a pulse to 0.17J / cm ² and a pulse, and preferably it may be irradiated with 0.11J / cm ² and a pulse to 0.17J / cm ² and a pulse, preferably 0.15J / cm ² and a pulse to 0.17J / cm ² and a pulse. In this range, a short wavelength (300 ~ 450nm) and long wave length I _2, that exist in the ^{_{(450 ~ 560nm) I 3 -}} , I 5 - to dissociate the ions effectively in a short time, and the transmittance is more than 80%, an iodine recombination under high temperature and high humidity There may be an effect of preventing a decrease in transmittance due to.

The femtosecond laser has a pulse width of 100 femtoseconds (fs) to 500 femtoseconds (fs), preferably 200 femtoseconds (fs) to 400 femtoseconds (fs), and 100 kHz to 500 kHz, preferably 150 kHz to 350 kHz in each of the wavelength ranges. Can be investigated with a frequency of Within the above range, there is no surface carbonization or laser hatching of the processed surface due to heat, and the precision at the irradiation interface is 50 μm or less, more preferably 10 μm or less.

The femtosecond laser may be irradiated for 1 second to 1000 seconds, for example, 1 second to 100 seconds in each of the wavelength regions. In the above range, it is possible to form a more neutral and high-transmissive portion without color change by increasing the irradiation time or number of times under the irradiation conditions without thermal deformation of the polarizer and the protective film.

The polarization canceling region may be formed by irradiating the polarizer with a femtosecond laser at the energy per pulse per unit area. However, the polarization canceling region may be formed by irradiating a femtosecond laser with the energy per pulse to a laminate in which a polarizer and a protective film are stacked on at least one surface of the polarizer.

As the protective film, a protective film commonly used as a protective film for a polarizer may be used. For example, the protective film is a cellulose type containing triacetylcellulose, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyester containing polybutylene naphthalate, cyclic polyolefin type, polycarbonate A protective film made of one or more of resins of polyethersulfone, polysulfone, polyamide, polyimide, polyolefin, polyarylate, polyvinyl alcohol, polyvinyl chloride, and polyvinylidene chloride. Can include.

The protective film may have a thickness of 10 μm to 100 μm, for example 10 μm to 60 μm. The lamination can be carried out with an adhesive, which is by conventional methods known to those skilled in the art.

Hereinafter, a region of the polarizing plate other than the polarization canceling region (polarization region), that is, a region where the femtosecond laser is not irradiated will be described.

The polarization region may have a single light transmittance at a wavelength of 380 nm to 780 nm of 20% or more, specifically 40% to 50%. In addition, the polarization canceling region may have a degree of polarization of 90% or more, specifically 90% to 100%. In the above range, image quality can be improved by implementing polarization performance in the display device.

In one embodiment, the polarization region has a ratio of light transmittance at wavelength 590 nm (light transmittance at wavelength 590 nm/light transmittance at wavelength 400 nm) (ratio of light transmittance) to light transmittance at wavelength 400 nm to be 0 to 2. I can. In addition, the ratio of the light transmittance of the polarization region is smaller than the ratio of the light transmittance of the polarization canceling region.

In one embodiment, the polarization region may have a maximum absorbance of 0.5 to 1.5 in a wavelength region of 380 nm to 420 nm. In addition, the maximum absorbance in the 380 nm to 420 nm wavelength region of the polarization region is greater or less than the maximum absorbance in the 380 nm to 420 nm wavelength region of the polarization cancellation region.

In one embodiment, the polarizing region is I ₃ ^- I ₅ of the concentration of the ^{ion-concentration} of the ion ratio ^{_{(I 5 - / I 3 -}} ) is equal to or greater than 2 specifically it may be a greater than 2 3 or less. Then, ₅ I of the polarizing areas ^- / I ₃ ^- I ₅ of the polarization is eliminated zone ^- greater than ^- / I _3.

Hereinafter, a display device according to an embodiment of the present invention will be described.

The display device of the present invention may include the polarizing plate of the present invention or the polarizer of the present invention. The display device may include a liquid crystal display device, an organic light emitting display device, and the like. In addition, the display device may include a display device including an infrared sensor.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, this is presented as a preferred example of the present invention and cannot be construed as limiting the present invention in any sense.

Specific specifications of the components used in the following Examples and Comparative Examples are as follows.

(1) Material of polarizer: polyvinyl alcohol film (VF-PE3000, Kuraray, Japan, thickness: 30㎛)

(2) Protective film: Triacetyl cellulose film (KC4UYW, Konica, Japan, 40㎛ thickness)

Example 1

The polyvinyl alcohol-based film washed with water was subjected to a swelling treatment in a water swelling bath at 30°C.

The polyvinyl alcohol-based film passed through the swelling tank was treated for 30 seconds to 200 seconds in a dyeing bath at 30° C. containing an aqueous solution containing 3% by weight of potassium iodide. The polyvinyl alcohol-based film passed through the dyeing bath was passed through a wet crosslinking bath, which is an aqueous solution of 30°C to 60°C containing 3% by weight of boric acid. The polyvinyl alcohol-based film passed through the crosslinking tank was stretched in an aqueous solution of 50°C to 60°C containing 3% by weight of boric acid, and stretched so that the total stretch ratio was 6 times to prepare a polarizer. A laminate was prepared by attaching a protective film to both sides of the prepared polarizer using an adhesive (Z-200, Nippon Goshei).

A polarizing plate, a layered product and cut into a predetermined size, laminated using a laser only some areas of the body by irradiating the femtosecond laser energy per pulse per unit area at a wavelength of 515nm that is 0.17J / cm ² and a pulse having a polarization resolved region Was prepared.

Examples 2 to 4

In Example 1, a polarizing plate having a polarization canceling region was manufactured in the same manner as in Example 1, except that the wavelength to which the femtosecond laser is irradiated and the energy per pulse per unit area were changed as shown in Table 1 below.

Comparative Example 1

In Example 1, a polarizing plate was manufactured in the same manner as in Example 1, except that the femtosecond laser was not irradiated at all.

Comparative Example 2

In Example 1, a femtosecond laser was irradiated so that the energy per pulse per unit area was 1.27 J/cm ² ㆍpulse at a wavelength of 515 nm to prepare a polarizing plate having a polarization canceling region.

Comparative Example 3

In Example 1, a femtosecond laser was irradiated so that the energy per pulse per unit area was 0.19 J/cm ² ㆍpulse at a wavelength of 515 nm to prepare a polarizing plate having a polarization canceling region.

Comparative Example 4

In Example 1, a femtosecond laser was irradiated so that the energy per pulse per unit area was 2.55 J/cm ² ㆍpulse at a wavelength of 515 nm to prepare a polarizing plate having a polarization canceling region.

Among the polarizing plates prepared in Examples 1 to 4 and Comparative Examples 2 to 4, the following physical properties were evaluated for the polarization canceling region. Since the polarizing plate prepared in Comparative Example 1 did not have a polarization canceling region, the following physical properties were evaluated for the entire polarizing plate. The results are shown in Table 1, Figs. 1, 2, 3, and 4 below.

(1) Maximum absorbance: The maximum absorbance at a wavelength of 380 nm to 420 nm was measured. The maximum absorbance was measured by JASCO's V730.

(2) Light transmittance (unit: %) and light transmittance ratio according to wavelength: The light transmittance according to the wavelength was measured using a JASCO V730 for a polarizing plate at a wavelength of 380 nm to 780 nm.

(3) Unit transmittance (unit:%) and polarization degree (unit:%) at wavelength 380nm to 780nm: Measure the unit transmittance and polarization degree according to the wavelength using JASCO's V730 for the polarization cancellation region at wavelengths 380nm to 780nm I did.

(4) I ₃ ^- to the ion I ₅ ^- ion concentration ratio ^{_{(I 5 - / I 3 -}} ): it was analyzed by Raman spectroscopy at a wavelength of 633 nm.

(5) Visual observation: The polarization cancellation region was observed with the naked eye. When it is neutral and there is no damage to the surface of the polarization canceling region ?; If it is not neutral and there is no surface damage of the polarization canceling region, it was evaluated as ○, if the surface damage of the polarization canceling region was not neutral and the surface damage was weak △, and if there was strong surface damage of the polarization canceling region without being neutral, it was evaluated as X.

Example Comparative example One 2 3 4 One 2 3 4 Femtosecond 515nm
(0.17) 515nm
(0.11) 515nm
(0.17) 515nm
(0.11) - 515nm
(1.27) 515nm
(0.19) 515nm
(2.55) - - 343nm
(0.17) 343nm
(0.11) - - - - maximum
Absorbance 0.99 1.23 0.95 1.12 1.28 2.12 1.79 2.22 ore
Transmittance @400
nm 43.4 31.6 43.0 32.1 29.9 10.1 15.9 11.4 @590
nm 86.6 51.8 86.0 60.1 35.3 56.1
49.6 80.1 Light transmittance ratio 1.99 1.64 2.0 1.87 1.18 5.55 3.12 7.03 Single transmittance 87 57 87 60 43 71 64 75 Polarization degree 3.5 48 3.6 46 99.99 24.9 36.9 21.5 I ₅ ^- / I ₃ ^- 1.4 2.0 1.5 2.0 2.7 2.3 2.2 2.5 Visual observation ◎ ○ ◎ ○ - x △ x

* In Table 1, the values in parentheses indicate energy per pulse per unit area.

As shown in Tables 1 and 4, the polarizing plate of the present invention satisfies all the ratios of the maximum absorbance and light transmittance in the polarization canceling region, so that the results are excellent when observed with the naked eye, so that the color and brightness are excellent, and there is no image distortion. You can shoot clear images. 2 and 3 show that the energy per pulse per unit area of the present invention is less than 0.17 J/cm ² ㆍpulse is significant in implementing the effects of the present invention.

On the other hand, in Comparative Examples 2 to 4, which do not satisfy the ratio of the maximum absorbance and light transmittance in the polarization canceling region, as in Tables 1 and 4, the polarization canceling region is not clear, and thus the effect of the present invention is achieved. It cannot be implemented properly.

Simple modifications or changes of the present invention can be easily implemented by those of ordinary skill in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (8)

As a polarizing plate having a polarizer and a protective film laminated on at least one surface of the polarizer,
The polarizing plate has at least a polarization canceling region in the in-plane direction,
The polarization canceling region has a maximum absorbance of 0.5 to 1.5 in a wavelength range of 380 nm to 420 nm,
In the polarization canceling region, the ratio of the light transmittance at the wavelength of 590 nm to the light transmittance at the wavelength of 400 nm is 1 to 2.
The method of claim 1, wherein the polarization is eliminated area I ₃ ^- I ₅ of the concentration of the ^ion in the ion concentration of the ratio is from 1 to 2, and a polarizing plate.
The polarizing plate of claim 1, wherein the polarization canceling region has a minimum absorbance of 0.1 to 1 in a wavelength range of 380 nm to 420 nm.
The method of claim 1, wherein the polarizing plate further comprises a polarizing region,
In the polarization region, the maximum absorbance in the wavelength 380 nm to 420 nm region is greater or less than the maximum absorbance in the 380 nm to 420 nm wavelength region of the polarization canceling region.
The polarizing plate according to claim 4, wherein a ratio of the light transmittance at a wavelength of 590 nm to the light transmittance at a wavelength of 400 nm in the polarization region is smaller than a ratio of the light transmittance at the polarization canceling region.
The method of claim 4, wherein the polarization domain is I ₃ ^- to the concentration of the ion I ^₅ of the ion ratio of the polarization relieve areas of concentration of I ₃ ^- I on the concentration of the ion ^₅ is greater than the concentration of the ion ratio Phosphorus, polarizer.
The polarizing plate of claim 1, wherein the polarizer includes a polarizer dyed with at least one of iodine and a dichroic dye.
A display device comprising the polarizing plate of any one of claims 1 to 7.

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